Corona assembly for electrostatic copy machines

ABSTRACT

A corona assembly for use with electrostatic copy machines, including a fixed bracket element of generally trapezoidal shape, a shield element having a first portion of corresponding configuration slideably engageable therewith, a corona wire of generally rectilinear configuration, a pair of planer diverging walls surrounding said corona wire, a pair of end blocks supported by said diverging walls at the end portions thereof, and supporting said wire at each of two terminals thereof, said diverging walls allowing ionized air disposed therebetween to readily escape to reduce the possibility of arcing.

United States Patent David L. Herman 63 Catherine Road, Scarsdale, N.Y.10583 [21 Appl. No. 834,336

[22] Filed June 18, 1969 [45] Patented Sept. 28, 1971 [72] inventor [54]CORONA ASSEMBLY FOR ELECTROSTATIC COPY MACHINES 1 Claim, 3 Drawing Figs.

[52] 11.8. C1 250/4952 ZC, 313/237, 313/238, 317/262, 355/3 [51] Int.Cl. 603; 13/00 [50] Field of Search 250/495 (60), 49.5 (61), 49.5 (62);317/262; 355/3; 313/237, 238

[56] References Cited UNITED STATES PATENTS 3,062,956 1 1/1962 Codichini250/495 (61) 3,471,695 10/1969 Hudson et a1 250/495 (61) PrimaryExaminer-James W. Lawrence Assistant Examiner-A. L. BirchAttorneys-James Albert Drobile and Robert Sherman Bramson ABSTRACT: Acorona assembly for use with electrostatic copy machines, including afixed bracket element of generally trapezoidal shape, a shield elementhaving a first portion of corresponding configuration slideablyengageable therewith, a corona wire of generally rectilinearconfiguration, a pair of planer diverging walls surrounding said coronawire, a pair of end blocks supported by said diverging walls at the endportions thereof, and supporting said wire at each of two terminalsthereof, said diverging walls allowing ionized air disposed therebetweento readily escape to reduce the possibility of arcing.

CORONA ASSEMBLY FOR ELECTROSTATIC COPY MACHINES This invention relatesgenerally to the field of xerographictype copying machines, and moreparticularly to an improved corona assembly suitable for use in suchdevices.

in the prior art, it is known to use a pair of such devices, whichoperate at very high voltages, in the order of 6,000 volts at 60 cyclefrequency. An electrostatic field is induced surrounding the wire, whichis used to charge the paper, portions ofthis charge being subsequentlyaltered by exposure to a light image, whereby toner particles willadhere to those areas of the paper which are not affected by light.

It is common practice to use an upper and a lower corona wire, which isnormally required where the copying device is operated in a highhumidity atmosphere. Unfortunately, this construction requires aduplication of parts, and in prior art constructions, there has been acommon tendency for the wire to arc with respect to surroundingstructure, and thus burn itself out.

it is among the principal objects of the present invention to provide animproved corona assembly, in which all of the paper charging functioncan be performed at a single station, using much higher voltages thanthose which have been previously used, and with incomplete absence ofarcing.

Another object of the invention lies in the provision of an improvedcorona wire assembly of the class described, which may be readilyremoved for servicing, and as readily reinstalled.

A further object of the invention lies in the provision of an improvedcorona wire assembly construction, in which the number of componentparts has been materially simplified, thereby reducing the process ofmanufacture and assembly.

Yet another object of the invention lies in the provision of an improvedcorona wire shield which is shaped to permit maximum charging of paperpassing therebeneath, and which includes means for venting ionized airto the outside atmosphere, thereby reducing the likelihood of arcingoccurring, with subsequent burn-out of the corona wire.

These objects, as well as other incidental ends and advantages, willmore clearly appear in the progress of the following disclosure, and bepointed out in the appended claims.

in the drawing, to which reference will be made in the specification,similar reference characters have been employed to designatecorresponding parts throughout the several views.

FIG. 1 is a fragmentary exploded view in perspective of an embodiment ofthe invention.

FIG. 2 is a fragmentary view in perspective of the embodiment showingthe parts in fully assembled condition.

FIG. 3 is a fragmentary view in perspective as might be seen from theleft-hand portion of FIG. 2.

in accordance with the invention, the device, generally indicated byreference character 10, comprises broadly: a mounting element 11, ashield element 12, and corona wire support means 13.

The mounting element 11 includes first and second bracket means 17 and18, respectively, each having a mounting flange 19 with a mounting slot20 whereby the same may be attached flange 22, and by a bend portion 23thereon to a horizontally disposed flange 24. A spot-welded area 25 oneach horizontal flange 24 interconnects with a trapezoidally shapedmember 26 including a base wall 27 and angularly disposed walls 28 and29 which define therebetween a dovetail" into which the shield element12 may be positioned.

The shield element 12 is preferably formed of sheet metal similar tothat of the mounting element 11, and includes a correspondinglytrapezoidally shaped portion 34 having a base wall 35 and a pair ofconverging walls 36 and 37. Interconnected with the walls 36 and 37 arediverging walls 38'and 39. An end wall 40 is formed integrally with thebase wall 35, and includes a pair of tabs 42 which are spot-welded toone end of each of the walls 38 and 39. it will be noted that thevertical portion 43 thereof defines a pair of openings 44 which, as willmore fully appear, permit the escape of ionized air surrounding thecorona wire support means 13. A central opening 45 permits the entry ofscrew means 46 which serve to position a part of the support means 13.

The support means 13 includes a pair of mounting blocks 50 and 51,preferably of die-cast construction, and defining converging sidewalls52, an end wall 53, an upper wall 54, and a lower wall 55. A rectangularcavity 56 opens to a threaded bore 57 in an inwardly disposed wall 58,whereby a wirerctaining member 59 may hepositioned by means of a screw60. The corona wire itself is a magnet tungsten wire loop ofapproximately 0.003 diameter, reference character 60.

Power is provided through conductors 63, which are connected to afiltered [2,000 volt source of well-known type. it will be observed thatthe angle of the diverging walls 38 and 39 allows pocketed ionized airto escape, through the one inch interstice between the free edgesthereof and the sensitized paper being charged (not shown). Because ofthe divergence of the walls, there is a smaller volume of air disposedwithin the shield, thereby permitting a quicker charge of the paper asit passes therebeneath.

i wish it to be understood that I do not consider the invention limitedto the precise details of structure shown and set forth in thisspecification, for obvious modifications will occur to those skilled inthe art to which the invention pertains.

I claim:

I. A corona assembly for use with an electrostatic copying devicecomprising: a mounting element, a shield element, and a corona wiresupport means; said mounting element having attachment means thereon forsecuring the same in fixed relation with respect to said copying device,and means forming a slideably engageable socket; said shield elementincluding a portion of configuration corresponding to that of saidsocket, a base wall lying in the first plane, a pair of sidewallsinterconnected to said base wall, and mutually diverging in a directionaway from said plane, said corona wire support means including first andsecond mounting blocks of tapered configuration and secured in contactwith said sidewalls at opposite ends thereof; said blocks formingopenings leading to the area enclosed by said sidewalls to permit thepassage of air therethrough; and corona wire-engaging means on saidblocks for supporting the same in rectilinear condition there between;said corona wire being supported substantially parallel to and adjacentthe free edges of said pair of sidewalls.

1. A corona assembly for use with an electrostatic copying devicecomprising: a mounting element, a shield element, and a corona wiresupport means; said mounting element having attachment means thereon forsecuring the same in fixed relation with respect to said copying device,and means forming a slideably engageable socket; said shield elementincluding a portion of configuration corresponding to that of saidsocket, a base wall lying in the first plane, a pair of sidewallsinterconnected to said base wall, and mutually diverging in a directionaway from said plane, said corona wire support means including first andsecond mounting blocks of tapered configuration and secured in contactwith said sidewalls at opposite ends thereof; said blocks formingopenings leading to the area enclosed by said sidewalls to permit thepassage of air therethrough; and corona wire-engaging means on saidblocks for supporting the same in rectilinear condition there between;said corona wire being supported substantially parallel to and adjacentthe free edges of said pair of sidewalls.